Self-locking device for couplings

ABSTRACT

A SELF-LOCKING THREADED ELECTRICAL CONNECTOR IS DISCLOSED. ONE OF TWO MATING SECTIONS OF THE CONNECTOR HAS A PLURALITY OF INDENTATIONS OR HOLES WHICH MOVE OVER A PLURALITY OF BALLS AS THE TWO MATING SECTIONS ARE THREADED TOGETHER. AS THE CONNECTOR IS TIGHTENED IT BECOMES MORE DIFFICULT TO MOVE THE INDENTATIONS PAST THE BALLS AND EVENTUALLY A LOCKED CONDITION IS ESTABLISHED. A TACTILE AND VISUAL INDICATION OF THE PROPERLY MATED CONDITION IS PROVIDED.

United States Patent O "ice 3,552,777 SELF-LOCKING DEVICE FOR COUPLIN GS Lawrence O. Heinrich, Hayward, and Joseph E. Wilcox, Redwood City, Calif., assignors to United Air Lines, Inc., Chicago, Ill., a corporation of Delaware Filed Feb. 23, 1968, Ser. No. 707,783 Int. Cl. F161 55/00 U.S. Cl. 285-81 9 Claims ABSTRACT F THE DISCLOSURE A self-locking threaded electrical connector is disclosed. One of two mating sections of the connector has a plurality of indentations or holes which move over a plurality of balls as the two mating sections are threaded together. As the connector is tightened it becomes more difcult to move the indentations past the balls and eventually a locked condition is established. A tactile and visual indication of the properly mated condition is provided.

BACKGROUND Field of invention The invention relates generally to threaded couplings and particularly to threaded electrical connectors.

Background of invention Threaded couplings are used in a wide variety of applications; Huid and pneumatic couplings and electrical connectors are examples. Because the threads of most couplings do not always provide an entirely reliable connection, frequently the couplings are locked with some other means. For example, in the aircraft industry it has been the practice to lock threaded electrical connectors with safety wire after they are threaded together. This technique has the disadvantage of being very time-consuming, especially in the crowded areas of aircraft.

Another disadvantage of threaded couplings, especially electrical connectors, is the dilculty the assembler encounters in determining when the connector is properly mated. In the case of electrical connectors, where each of the many electrical contact pins may require up to live pounds of force each to establish a proper fit, the connector may feel tight before the force required to establish the mated condition is applied.

BRIEF DESCRIPTION OF THE INVENTION It is therefore an object of the present invention to provide a novel self-locking coupling.

A further object of the present invention is to provide a novel self-locking device which can be incorporated in one-half of a mating connector pair.

It is a further object of the present invention to provide a novel self-locking threaded coupling which provides a visual or tactile indication of a properly mated condition.

Brieily, these objects are accomplished in a coupling which includes two mating sections, one of which has a threaded rotatable portion and a coaxial stationary portion. One of these two portions carries a plurality of axially movable elements, preferably balls, and the other portion contains a surface having a plurality of indentations which engage and disengage the balls as the threaded portion is rotated. As the mating sections are threaded together and the coupling becomes tighter, the balls are urged more firmly toward the indentations and eventually establish a locked conditions. The visual and tactile indication is provided by a window in the rotatable portion which exposes an axially movable part (pressure plate) of the stationary portion when the mated condition is obtained.

3,552,777 Patented Jan. 5, 1971 BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT The following description of the present invention, referring to the two gures of the drawing, relates to an electrical connector. The present invention is particularly useful with electrical connectors which might be used, for example, in the aircraft industry. However, the invention is in no sense limited to electrical connectors but may be used with other types of couplings, pneumatic or hydraulic couplings being other examples.

The illustrated connector includes basically two sections 10, 11 threaded for engagement with each other. A nut 12 on the rst section 10 engages a threaded annular ange 13 on the second section. The nut 12 is rigidly secured, by a press t, or with suitable fasteners, to a rotatable annular sleeve 15 having a roughened surface, hexagon., etc. 16 for enabling the assembler to secure a lirm grasp. One end of the annular sleeve 15 has an annular plate or flange 18 having a plurality of ball receiving indentations which may be, as illustrated, a plurality of axially extending holes 19.

The rotatable sleeve 15 is coaxial with a shell 20 which contains the necessary electrical sockets (not shown) for electrical connection with mating contact pins (not shown) in the other section 11 of the connector. The construction of the contact pins and sockets is well known in the art and the details have not been illustrated in the drawing.

As best illustrated in the exploded View of FIG. 2, the shell 20 includes a first cylindrical section 21 containing the electrical sockets, a threaded section 22 which enables mechanical connection to the electrical cablefwhich the connector terminates, and a radially disposed ange 23 between the other two portions 21, 22. The ilange 23 has a plurality of axially disposed sockets 25 which'mount a plurality of axially movable elements 26 which are 'preferably balls.

A rst annular pressure plate 30 ts over the cylindrical section 21 for engagement with the plurality of yballs 26. A wave spring 31 ts between this pressure plate 30 and a second similar pressure plate 32 which also ts over the cylindrical section 21. The second pressure plate 32 engages one end 33 of the nut 12 attached to the rotatable sleeve 15.

The operation of the electrical connector is best illustrated by FIG. 1. As the nut 12 is threaded onto the threaded portion 13 by rotation of the sleeve 15, the annular edge 35 of the threaded portion 13 engages the second pressure plate 32. The pressure exerted on this pressure plate 32 is transmitted through the wave spring 31 and first pressure plate 30 to the plurality of balls 26 mounted in the flange 23. Thus the balls 26 are urged toward the flange 18 on the rotatable sleeve 15. As the sleeve 15 is rotated to tighten the connection, the holes 19 engage and disengage the balls 26 which move axially under the influence of the spring 31. As the threaded connection becomes tighter and the pressure plate 32 moves closer to the pressure plate 30 thereby exerting more pressure on the balls 26, it becomes more diicult to move the sockets 19 past the balls 26. Eventually, it becomes very dificult for the operator to rotate the sleeve 15 in either direction. This is the locked condition of the connector.

When the connector is in the locked condition, the

second pressure plate 32 is positioned under the windows 37 in the rotatable sleeve 15. A tactile indication of the locked condition is therefore provided since the operator may feel the pressure plate 32 through a window 37. Also, the edge of the plate 32 is preferably painted a bright color such as high visibility orange to provide a visual indication of the locked condition.

While one embodiment of the invention has been described in detail, the invention is in no sense limited thereto.

What is claimed is:

1. A coupling comprising iirst and second sections threaded for connection by relative rotation, said first section having first and second portions, the first being rotatable relative to both the second section and the second portion to form said connection, one of said portions carrying a plurality of elements axially movable with respect to said portion and the other of said portions having axially recessed indentations for engaging said elements, at least one of said elements or indentations having a camming surface for permitting cooperative movement between said elements and indentations, means on said second section for causing said indentations and said elements to be urged together as said first and second sections are rotated to form said connection which results in a locking force which is proportional to the torque applied during tightening whereby the locking force becomes gradually greater as said sections are tightened.

2. The coupling of claim 1 further including spring bias means and wherein said elements are pushed by said second section through said spring bias means.

3. The coupling of claim 2 wherein said spring bias means includes rst and second pressure plates separated by a spring, one of said pressure plates being adapted for contact with said elements and the other of said pressure i plates being adapted for connection to a portion of said second section.

4. The coupling of claim 1 wherein said first portion is an annular sleeve surrounding the second portion with a radially disposed flange in which the indentations are formed, and said second portion includes a radially disposed flange which mounts said elements.

5. The coupling of claim 4 wherein said sleeve has at least one window and a predetermined part of said first section is exposed beneath said window when said sections are properly mated.

6. 'Ille coupling of claim 5 further including first and second pressure plates separated by a spring and mounted CFI 4 on said connector, one of said pressure plates engaging said elements and the other of said pressure plates engaging a part of said second section, wherein said portion exposed beneath said window is the edge of said second pressure plate.

7. The coupling of claim 6 wherein said elements are balls.

8. An electrical connecting device comprising first and second sections threaded for engagement with each other, a generally cylindrical shell portion having a flange, a plurality of balls mounted in the flange and restricted in their motion with respect thereto to rotational and axial directions, said first section including a sleeve coaxial with said shell and a llange having a plurality of sockets for axial engagement with said balls, first and second annular plates positioned on the shell, the first plate being adjacent the llange on the shell and the second plate being adapted to contact the end of said second section, and a resilient member positioned between the two annular plates whereby a locking force proportional to the torque applied during tightening is established between said rst and second sections as the sections are threaded together.

9. The device of claim 8 wherein said sleeve covers said annular plates and includes at least one window for exposing the edge of the second plate when the first and second sections are securely threaded together.

References Cited 12/1960 Great Britain 339-186M 0 THOMAS F. CALLAGHAN, Primary Examiner U.S. Cl. X.R. 

